const env = require('config.js'); //配置文件，在这文件里配置你的OSS keyId和KeySecret,timeout:87600;

const base64 = require('base64.js');//Base64,hmac,sha1,crypto相关算法
require('hmac.js');
require('sha1.js');
const Crypto = require('crypto.js');

/*
 *上传文件到阿里云oss
 *@param - filePath :图片的本地资源路径
 *@param - dir:表示要传到哪个目录下
 *@param - successc:成功回调
 *@param - failc:失败回调
 */ 
const uploadFile = function (filePath, dir, successc, failc) {
    if (!filePath || filePath.length < 9) {
        wx.showModal({
            title: '图片错误',
            content: '请重试',
            showCancel: false,
            })
        return;
    }
    
    console.log('上传图片.....');
    //图片名字 可以自行定义，     这里是采用当前的时间戳 + 150内的随机数来给图片命名的
    const aliyunFileKey = dir + new Date().getTime() + Math.floor(Math.random() * 150) + '.png';
    const aliyunServerURL = env.uploadImageUrl;//OSS地址，需要https
    const accessid = getApp().globalData.aliOSS.accessKeyId;
    if (accessid == '' || accessid == null) {
        wx.showToast({
            title: '请稍后重试！'
        })
        return;
    }
    const policyBase64 = getPolicyBase64();
    const signature = getSignature(policyBase64);//获取签名
    wx.uploadFile({
        url: aliyunServerURL,//开发者服务器 url
        filePath: filePath,//要上传文件资源的路径
        name: 'file',//必须填file
        formData: {
            'name': filePath,
            'key': aliyunFileKey,
            'policy': policyBase64,
            'OSSAccessKeyId': accessid,
            'signature': signature,
            'success_action_status': '200',
        },
        success: function (res) {
            console.log(res);
            if (res.statusCode != 200) {
                failc(new Error('上传错误:' + JSON.stringify(res)))
                return;
            }
            successc(aliyunServerURL+aliyunFileKey);
        },
        fail: function (err) {
            console.log(err);
            err.wxaddinfo = aliyunServerURL;
            failc(err);
        },
    })
}

const getPolicyBase64 = function () {
  let date = new Date();
  date.setHours(date.getHours() + env.timeout);
  let srcT = date.toISOString();
  const policyText = {
    "expiration": srcT, //设置该Policy的失效时间，超过这个失效时间之后，就没有办法通过这个policy上传文件了 
    "conditions": [
      ["content-length-range", 0, 5 * 1024 * 1024] // 设置上传文件的大小限制,5mb
    ]
  };

  const policyBase64 = base64.encode(JSON.stringify(policyText));
  return policyBase64;
}

const getSignature = function (policyBase64) {
    const accesskey = getApp().globalData.aliOSS.accessKeySecret;

    const bytes = Crypto.HMAC(Crypto.SHA1, policyBase64, accesskey, {
        asBytes: true
    });
    const signature = Crypto.util.bytesToBase64(bytes);

    return signature;
}

module.exports = uploadFile;